Production of ethylene, butadiene, carbon black feedstock and benzene from a cracked naphtha



R. E. GILLILAND ETAL 3,281,351

N CARBON BLACK FE HTHA Oct. 25, 1966 EDSTOCK PRODUCTION OF ETHYLE E,BUTADIENE,

AND BENZENE FROM A CRACKED NAP 4 Sheets-Sheerl l Filed OCC. 16, 19643,28 ,351 EEDsTocK ETAL Oct. 25, 1966 R. E. GILLILAND HYLENE, BUTADIENE,

PRODUCTION OF ET CARBON BLACK F AND BENZENE FROM A CRACKED NAPHTHA 4Sheets-Sheet Filed Oct. 16, 1964 0d 25, 1965 R. E. GILLILAND ETALPRODUCTION OF ETHYLENE, BUTADIENE, CARBON BLACK FEEDSTOCK AND BENZENEFROM A CRACKED NAPHTHA 4 Shee 11s-Sheet 5 Filed OCb. 16, 1964 Oct. 25,1966 R E. GILLILAND ETAL 3,281,351

PRODUCTION OF ETHYzLENE, BUTADIENE, CARBON BLACK FEEDSTOCK Filed Oct.16, `1964 AND BENZENE FROM A CRACKED NAPHTHA 4 Sheets-Sheet 4 ,ef 2 ATTOPN VS United States Patent O 3,281,351 PRDUCTIUN F ETHYLENE,BUTADEENE, CAR- BON BLACK FEEDSTCK AND BENZENE FROM A CRACKED NAPHTHARobert E. Gilliland, Donald 1K. MacQueen, and Rolland E. Dixon,Bartlesville, Okla., assignors to Phillips Petroleum Company, acorporation of Delaware Filed (let. 16, 1964, Ser. No. 404,333 4 Claims.(Cl. 208-67) naphtha cracking and olefin dehydrogenation are combned ina process wherein ethylene and butadiene are produced. By the practiceof our invention, relatively low priced products of that reaction are-combined and processed for the production of relatively high pricedproducts.

An object of our invention is to produce ethylene, butadiene, benzeneand a carbon black feed stock from naphtha.

Another object of our invention is to produce a high quality carbonblack feed stock and benzene from fuel oil, gasoline, and butene deoilerkettle products from a butadiene and ethylene producing process.

Other aspects, objects and the advantages of our invention are apparentin the written description, the drawing and the claims.

According to our invention, a hydrocarbon stream is cracked and theeffluent separated to produce fuel oil, gasoline, butene, butadiene,propylene and ethylene. The butadiene rand ethylene are recovered asproducts. The butene is dehydrogenated to produce additional butadiene.The propylene is disproportionated to produce additional quantities ofethyene and butene, with the butene being fed to the dehydrogenationstep. Isobutylene removed from the butene prior to dehydrogenation, thegasoline and the fuel oil, are hydrotreated and the effluent solventextracted to remove aromatics, the parains and olens being recycled tothe cracking step. The aromatic portion is further separated to producebenzene and a high aromatic stream which is blended with the fuel oil toproduce a high quality carbon black feed stock. The eflluent of thebutene dehydrogenation and the C2 fraction of the propylenedisproportionation are recycled to the separation train of thehydrocarbon cracking eiiiuent.

In this application, disproportionation is used to mean the conversionof a hydrocarbon into similar hydrocarbons of higher and lower numbersof carbon atoms per molecule. The process is especially applicable tonontertiary base aliphatic olefins, that is, olens having no carbonchain branching at a double bond carbon atom, having from 3 to 6 carbonatoms per molecule. When propylene is disproportionated, approximatelyequimolar quantities of ethylene and butenes are produced.

Suitable disproportionation catalysts for the practice of our inventioninclude oxides, sulfides and carbonyls of molybdenum and tungsten,supported on silica, alumina, or silica-alumina, or any other suitabledisproportionation catalysts. Operating conditions suitable for thecatalyst and feed are selected.

Details of some suitable disproportionation processes are given incopending applications Serial No. 307,371,

ICC

Hecklesberg, filed September 9, 1963; Serial No. 313,309, Banks, filedSeptember 27, 1963, now abandoned; Serial No. 336,624, Hecklesberg, ledJanuary 9, 1964; and Serial No. 94,996, Banks, led March 13, 1961.

Catalysts, conditions, etc., for use in the dehydrogenation step forproducing diolefins from olen feed stocks are well known and need not bediscussed in detail. For example, a suitable dehydrogenation process isdisclosed in U.S. Patent No. 2,866,790.

Similarly, conditions and catalysts for the hydr-otreating steps arewell known. For example, the process disclosed in Hydrocarbon Processingand Petroleum Rener, November 1962, vol. 4l, No. 1l, pages 201-202, issuitable. Suitable catalysts include molybdenum sulfide, nickel sulfide,etc., on alumina or clay.

In the drawing, FIGURE 1 ilustrates a unitized system for naphthacracking, propylene disproportionation, butene dehydrogenation,hydrotreating and aromatic extraction.

FIGURE 2 is a unitized system for naphtha cracking, propylenedisproportionation, butene dehydrogenation, hydrotreating and aromaticextraction, illustrating separation facilities in more detail.

FIGURE 3 illustrates a unitized system for naphtha cracking, propylenedisproportionation, butene dehydrogenation, hydrotreating and aromaticextraction, utilizing a simplified separation system.

FIGURE 4 illustrates, in somewhat more detail, hydrotreating andaromatic extraction facilities suitable for use in the system of FIGURE1, FIGURE 2 or FIGURE 3.

In the system illustrated in FIGURE l, a hydrocarbon suitable forcracking is fed into naphtha cracking reactor 11, and the efuent passedthrough conduit 13 into separation unit 14. From separation unit 14 afuel oil stream is removed through conduit 16, a gasoline stream throughconduit 17, a C4 hydrocarbon stream through conduit 18, and a C3hydrocarbon stream `through conduit 19.

The C4 stream of conduit 18 is passed into a butadiene recovery unit 21from which a purified butadiene stream is removed through conduit 22 anda butene-isobutylene containing stream removed through conduit 23 andpassed into isobutylene removal unit 24. The butene containing streamhaving isobutylene removed therefrom is passed through conduit 26 intobutene deoiling unit 27 from which a purified butene stream is passedthrough conduit 28 into butene dehydrogenation unit 29. The effluentfrom unit 29 is passed through conduit 31 and returned to separationunit 14.

The C3 stream of conduit 19 is passed into disproportionation reactor33. The disproportionated effluent is passed through conduit 34 intoseparation unit 36 from which a C4 olefin stream is passed into butenedeoiling unit 27 through conduit 37. The lighter fractions of theeffluent in conduit 34 are returned through conduit 38 for recycle tothe disproportionation reactor 33. When desired, a separate stream of C2and lighter hydrocarbons can be removed from separation unit 36 throughconduit 41.

The gasoline Stream in conduit 17, the isobutylene stream in conduit 42and the kettle product from butene deoiling unit 27 in conduit 43 areall fed into hydrotreating unit 46. Hydrogen is added through conduit47. The euent is passed into aromatic extraction unit 4S from which theparainic and olefinic portions are returned through conduit 49 to napthacracking unit 11 while the aromatic portions are taken through conduit51, into a benzene separation unit 52 from which benzene is removedthrough conduit 53 and a highly aromatic heavier fraction removedthrough conduit 54 for blending with fuel oil in conduit 16 to .producethe carbon black feed stock which is removed through conduit 56.

In the system illustrated in FIGURE 2, a naptha stream is passed. intonaptha cracker 61 through conduit 62 and the etiluent is passed to heatrecovery and quench 63 through conduit 64. In the heat recovery andquench section 63, the eliiuent from the naptha cracking furnace isquenched in waste heat boilers, and a two-stage quench tower providesfor subsequent cooling by passing vapors upwardly through the tower, thelower section of which is an oil quench and the upper section a multiplewater quench. For further conservation of heat, steam is generated inwaste heat boilers in the cracking furnace stack gas system. A fuel oilcondenses in the quench tower and is removed as a side stream from thecirculating quench oil through conduit 65.

The eiuent from the quench tower is compressed and fed. to debutanizer66 as one vapor stream and two condensate streams. This is accomplishedby passing effluent from heat recovery and quench section 63 throughcompressor 67 into ash chamber 68, the condensate being passed todebutanizer 66 through conduit 69 while the overhead is compressed incompressor 71 and passed to flash chamber 72 from which the condensateis passed to debutanizer 66 through conduit 73 and the vapor istransferred to debutanizer 66 through conduit 74. A debutanized gasolinestream is removed as a bottoms product from debutanizer 66 throughconduit 76.

The overhead is further compressed in compressor 77 and passed throughan amine treating unit for the removal of CO2 and H28. The effluent fromamine treater 78 is passed to caustic wash and dry unit 79 where theefliuent from the amine unit is caustic washed to remove the last tracesof acid gases, then water washed. to prevent caustic carry over. Theefuent from caustic wash and dry unit 79 is fed to depropanizer 80. Thebutene and heavier bottoms product from depropanizer 80 is passedthrough conduit 81 to the butadiene recovery and purification unit, thefirst stage being a furfural absorber S2. Butadiene is absorbed inabsorber 82 and the rich furfural passes into furfural stripper 83,furfural being returned to furfural absorber 32 through conduit 84. Thebutadiene rich stream passes through conduit 85 into butadiene column86. A high purity butadiene stream is taken overhead through conduit 87,and the bottoms product, comprising butenes, is passed through conduit88 into conduit 89 which feeds butene deoiler 90.

The overhead from the furfural absorber is separated into two streams,one stream being passed through conduit 91 into `a cold acid isobutyleneremoval unit 92 while the other stream is passed. through conduit 93into butane extraction column 94 which controls the build-up of butanesin the system by removal from this side stream. The debutanized streamfrom extraction column 94 is passed through conduit 95 and recombinedwith the stream being fed to isobutylene removal unit 92. The deoiledoverhead from butene deoiler 90 is passed into butene dehydrogenationreactor 96 and the eiuent passed through conduit 97 and returned to theseparation system for the efiiuent from naphtha cracker 61.

Preferably, the effluent from the dehydrogenation reactor is quenched ina waste heat boiler and is cooled in a stacked oil and water quenchtower similar to the naphtha cracking furnace effluent heat recovery andquench system.

The propane and lighter fraction from depropanizer 80 is compressed incompressor 101 and, passed into the primary acetylene removal reactor102. This unit is operated under high selectivity, low conversionconditions to remove the bulk of C2 and C3 acetylenes, piperidine, andbutadiene, without significant losses of ethylene or propylene.Preferably, this stream again is dried to remove water formed fromoxygen compounds in the acetylene removal reactor feed and then fed tocooling train 103. Cooling train 103 is a series of refrigerated andrecycled. cooled heat exchangers and a centrifugal expander, withcorresponding required auxiliary surge tanks,

pumps, etc. A hydrogen rich vapor and a methane rich vapor are removedas by-products, and the remainder of this stream is liquefied and sentto demethanizer 104. Preferably, the demethanizer overhead is recycledthrough the cooling train for sensible heat recovery and then isproduced as a fuel gas by-product. The demethanizer bottoms, primarilyethane, ethylene, propane and propylene, are fed through conduit 106into deethanizer 107. The deethanizer overhead is fed through conduit108 into secondary acetylene removal reactor 109, operated at highconversion and low selectivity, t-o bring the acetylene content to a lowvalue. The effluent from the secondary acetylene removal reactor is fedto ethylene fractionator 111 and separated into an overhead ethylenestream and, a bottoms product ethane stream. The ethane stream isremoved through conduit 112 while the ethylene stream is passed throughconduit 113 to methane stripper 114, with high purity ethylene beingremoved through conduit 116. Where sufficient demand for ethyleneexists, the produced ethane can be cracked to produce additionalquantities of ethylene. The overhead from methane stripper 114 containssuicient ethylene to justify reseparation, and this stream is recycledto the suction of cornpressor 101 through conduit 117 as shown.

The bottoms product from deethanizer 107 is passed through conduit 121to an acetylene removal unit 122. This unit is operated at highconversion, low selectivity, to reduce the methyl acetylene andpropadiene concentration suiciently to prevent damage to thedisproportionation catalyst. The eiuent from acetylene removal units 122is fed to disproportionation reactor 123. The effluent from reactor 123is passed through conduit 124 to propylene splitter 126. The overhead,comprising ethylene and lighter, is recycled to deethanizer 107 throughconduit 127. A side draw, primarily propylene and propane, is recycledthrough conduit 123 to the inlet of reactor 123. The bottoms product,propane and heavier, is fed to depropanizer 131 through conduit 132, andthe bottoms product from depropanizer 131 is fed through conduit 133into the inlet of butene deoiler 90.

The gasoline stream in conduit 76, the stream from isobutylene removalunit 92, comprising isobutylene in the form of an isobutylene polymer,in conduit 136, and the butene deoiler bottoms in conduit 137, arepassed to hydrotreater 138 along with hydrogen from conduit 139. rl`heefliuent from hydrotreater 138 is passed to aromatic extraction unit141, the parains and olefins being recycled to cracking through conduit142 while the aromatics are passed through conduit 143 to a benzeneseparation unit 144, the benzene being removed overhead and a highlyaromatic heavier hydrocarbon stream being removed from the bottomthrough conduit 146. The bottoms product from benzene separation unit144 is combined and blended with fuel oil in conduit 65 to produce acarbon black feed stock of the desired aromaticity, which is removedthrough conduit 147.

In the system of FIGURE 3, the operation is somewhat similar to theoperation of the system illustrated in FIGURE 2, but a much simplerseparation system is utilized. A naphtha stream is passed into naphthacracker 151 through conduit 152 and the efliuent passed to heat recoveryand quench 153 through conduit 154. The heat recovery and quench section153 can be similar to the corresponding section 63 of FIGURE 2. Theefliuent from the quench tower is compressed in compressor 156 andcompressor 157 and passed into flash chamber 158, the condensate fromflash chamber 158 being passed to ash chamber 159. The overhead fromflash chamber 158 is passed through caustic Wash and dry unit 161 andcompressor 162 into flash chamber 163. The overhead from ash chamber 143is passed through a heat exchange train 164 into a ash chamber 166. Thecondensate from chamber 166 is passed into demethanizer 167. The bottomsproduct from demethanizer 167 is passed into acetylene removal unit 168and then to ethylene fractionator 169 from which an ethylene productsteam is removed overhead and ethane removed from the bottom.y Thecondensate from flash chamber 163 is passed through a C3 acetyleneremoval unit 171 into product splitter 172. The overhead from Hashchamber 159 also passes through acetylene removal unit 171 into productsplitter 172. 'Ihe overhead from product splitter 172 is passed into thestream comprising the bottoms product frem demethanizer 167 and passedthrough acetylene removal unit 168 into ethylene fractionator 169. Aside draw is taken from product splitter 172 and passed to propylenedisproportionation unit 173, with the product from unit 173 beingreturned to product splitter 17 2.

The bottoms product from products splitter 172 is passed into furfuralabsorber 176. The rich furfural, comprising butadiene, is passed intofurfural stripper 177 and the butadiene containing stream is strippedfrom the furfural and is passed into the butadiene column 178. Butadieneis removed overhead from column 178 with the bottoms product beingrecycled to furfural absorber 176. The rainate from absorber 176 ispassed into isobutylene removal unit 178, with isobutylene being removedtherefrom through conduit 179 and the remaining stream passed to butenedeoiler 180. A slip stream, from conduit 181, which transports therainate from absorber 176 to isobutylene removal unit 178, is takenthrough butane extractor 182. Butanes are removed as a rainate fromextractor 182 while the butenes are recovered and returned to conduit181. The overhead from butene deoiler 180 is passed into butenedehydrogenation unit 186 and a product stream is returned to compressor156.

A gasoline stream in conduit 186, the isobutylene t stream in conduit179, and the bottoms product from butene deoiler 180 in conduit 187, arefed into hydrotreater 191, along with hydrogen from conduit 192. Theetlluent from hydrotreater 191 is fed to aromatics extraction unit 193with paraiiins and oleiins being returned to naphtha cracking throughconduit 194 while the aromatic concentrate is passed through conduit 196into a benzene separation unit 197. Benzene is taken overhead from thisunit while a heavier hydrocarbon highly aromatic stream is removed fromthe bottom and combined and blended with fuel oil from conduit 198 toproduce a carbon black feed stock having a desired aromaticity.

It will be recognized that many elements of a complete commercial planthave been omitted from the description of the disclosed embodiments ofour invention in the interests of clarity and brevity. In manyinstances, specific variations can be utilized. For example, anysuitable disproportionation catalyst can be used in thedisproportionation reactor, any suitable butene dehydrogenation catalystcan be used in the butene dehydrogenation reactor and any suitablehydrotreating catalyst can be used in the hydrotreating reactor.Similarly, separation steps such as fractional distillation, solventextraction, etc., can be utilized where appropirate and substituted byone skilled in the art. Our invention lies in combination, and,therefore, is not limited to a specific type of cracking,disproportionation, dehydrogenation, or hydrotreating reactor, orspecific puriiication or separation steps. Many details of equipmentneeded in a commercial plant have been omitted, including for example,such things at pumps, valves, control equipment, etc.

FIGURE 4 illustrates the hydrotreating, aromatics eX- traction, andaromatics separation of FIGURE 2 in more detail. Gasoline from conduit76, isobutylene from conduit 136 and the butene deoiler bottoms inconduit 137 are heated in a heater 201 and fed into a first stagehydrotreater 202. The effluent from treater 202 is treated in a secondstage treater 203, the efuent from the treater 203 being condensed incondenser 204 and passed into high pressure separator 206. If desired, aportion of the effluent from treater 202 can be by-passed throughconduit 207. The gaseous overhead from separator 206, comprisinghydrogen, is recycled or vented as desired or needed While the bottomsproduct is transmitted to stabilizer 208. The overhead product fromstabilizer 208 is fuel gas which is removed through conduit 140, whilethe bottoms are passed to separator 209 from which is taken a heavystream through conduit 148 with the overhead being taken to aromaticextraction 141 which includes aromatic extractor 211 and stripper 212.The recycled parati-in and olen stream is taken through conduit 142 andthe aromatic stream to benzene separation unit 144 through conduit 143.The benzene outlet 145, the aromatic stream 146, the fuel oil stream 65,and the carbon black feed stock stream 147 are described above inconnection with FIGURE 2.

EXAMPLE In an example of the operation of our invention according toFIGURE 2, the stream fed to cracking reactor 61 comprises a wide rangenaphtha made from a Kuwait crude, the naphtha having a boiling range ofto 352 F., a density of 64.3 API and comprising 72 volume percentparaffin (44 per-cent N-paran), 18 percent by volume naphtha and 10percent by volume aromatics, with substantially no olens. The operatingconditions of the various units of the system are given in Table I, andthe material balance is presented in Table II, the numbers of thesestreams corresponding with numbers in FIG- URE 2.

TABLE L OPERATING CONDITIONS 61 Naphtha cracking furnace Steam/HC ratio:0.7 Outlet pressure: 25 p.s.i.a. Outlet temperature: 1450 to l500 F.Heat recovery and quench Steam generated 315 p.s.i.a. Quench towerinlet: 20 p.s.i.a., 500 F. Quench tower outlet: 18 p.s.i.a., 105 F. lstcompressor stage Inlet: 17.7 p.s.i.a., 100 F. Outlet: 48 p.s.i.a., 215F. 2750 horsepower, 27.435 c.f.m. 1st flash 42 p.s.i.a., 60 F. 2ndcompressor stage Inlet: 42 p.s.i.a., 60 F. Outlet: 118 p.s.i.a., 188 F.2350 horsepower, 7992 c.f.m. 2nd flash p.s.i.a., 60 F. Debutanizer Reuxdrum: 100 p.s.i.a., 62 F. Reboiler vapor: 110 p.s.i.a., 313 F. 3rdcompressor stage Inlet: 100 p.s.i.a., 62 F. Outlet: 255 p.s.i.a., 185 F.2150 horsepower, 3479 c.f.m. Amine treater Absorber tower: 250 p.s.i.a.;160 F. in, 135 F.

out 95% CO2 removal Caustic wash and dry Caustic tower: 245 p.s.i.a.,135 F. Water Wash tower: 250 p.s.i.a., 135 F. Dryer inlet: 230 p.s.i.a.,60 F. Dryer outlet: 210 p.s.i.a., 60 F. Depropanizer Reflux drum: 200p.s.i.a., 0 F. Reboiler vapor: 210 p.s.i.a., 202 F. Furfural absorberReflux drum: 100 p.s.i.a., 138 F. Reboiler vapor: p.s.i.a., 303 F.Furfural stripper Reflux drum: 65 p.s.i.a., 110 F. Reboiler vapor: 80p.s.i.a., 329 F.

101 4th compressor stage Inlet: 198 p.s.i.a., 60 F. Outlet: 525p.s.i.a., 230 F. 1750 horsepower, 1292 c.f.m.

102 Primary acetylene removal unit Girdler G-73 catalyst Reactorconditions: 520 p.s.i.a., 350 F.

103 Cooling train 13 refrigerated and interchanger units in series 97horsepower centrifugal expander Inlet: 485 p.s.i.a., 55 F. Outlets:

480 p.s.i.a., 10 F. 470 p.s.i.a., 84 F. 466 p.s.i.a., 150 F. Hydrogenseparator: 455 p.s.i.a., 200 F.

Demethanizer Reflux drum: 425 p.s.i.a., 142 F.

Reboiler vapor: 435 p.s.i.a., 52 F. Deethanizer Reflux drum.: 400p.s.i.a., 14 F.

Reboiler vapor: 410 p.s.i.a., 147 F. Secondary acetylene removal unitGirdler G-58 catalyst Iig/C2H2 ratio:

Reactor conditions: 395 p.s.i.a., 350 F. Ethylene fractionator Refluxdrum: 290 p.s.i.a., 25 F.

Reboiler vapors: 300 p.s.i.a., 3 F. Methane stripper Reflux drum: 300p.s.i.a., 29 F.

Reboiler vapors: 310 p.s.i.a., 17 F. C3 acetylene removal unit GirdlerG-55 catalyst H2/C3H4 ratio: 2.0

Reactor conditions: 485 p.s.i.a., 350 F. Propylene disproportionationunit Reactor conditions: 460 p.s.i.a., 850 F. Propylene splitter Refluxdrum: 420 p.s.i.a., 114 F.

Reboiler vapor: 430 p.s.i.a., 239 F. Propane stripper Reflux drum: 265p.s.i.a., 123 F.

Reboiler vapor: 275 p.s.i.a., 246 F. Hydrotreater Catalyst Reactorconditions Aromatic extraction unit Benzene separation unit TABLEII.MATERIAL BALANCE-POUNDS PER HOUR STREAM NUMBER Component 624-142 6469 73 72a 46 81 84 85 87 88 89 91 93 Hydrogen 634 2 0 Carbon Monoxide. 00 0 Carbon Dioxide 10 31 0 Methane 12, 036 30 0 Acetylenes 24 33 6Ethylene. 18, 898 183 Ethane 6, 124 91 Propylene 15, 414 739 Propane 1,372 120 Isobutane 243 94 Isobutene 2, 006 321 Butene-l 1, 345 1,433Butadiene 2, 745 1, l431 n-Butane 602 287 Trans-Buteue-2. 1, 777 2, 396Cis-Butene-2 95 1, 727 (l5-400 Gasoline. 105, 600 34, 841 31, 242Heating Oil 6, 229 0 Total Hydrocarbons Furfural Water TABLEII.-Continued Component 95 97 106 108 112 113 116 117 121 124 127 128132 133 Hydrogen 557 Carbon Monoxide. Carbon Dioxide Methane AcetylenesEthylene Ethane. Propylene- Propane Isobutane- Isobutene...

Butene-l. Butadiene n-Butane TransButene-2 Gis-Butene-Z C4400 Gasoline.

Heating Oil Total Hydr0carb0ns 84, 775

TABLE II.-Continued lisobutylene Hydrogen Fuel Gas GaseA Recycle Freshline Component Heavier Benzene Polymer Naphtha Naphtha Hydrogen CarbonMonoxide Carbon Dioxide Methane Acetylenes Ethylene Ethane PropaneIsobutane Isobutene Butene-l 51 Butadiene 1 n-B utane 6 Trans-Butene-2 645 4g Cis-Butene-2 293 (J5-400 F (Gasoline) 1 34,480 400 F-l- (Fuel Oil)Total Hydrocarbons 1 (J5-400 F Composition:

Benzene Heavy Aromatics. N ori-Aromatics- Reasonable variation andmodifi-cation are possible Within the scope of our invention which setsforth method and apparatus for producing ethylene, butadiene, benzene,

recycling parafns and olens from said aromatic eX- traction zone to saidnaphtha cracking Zone; removing a C3 hydrocarbon stream from saidseparaand a carbon black feed stock, along with by-products, tion zoneand passing said C3 hydrocarbon stream from a hydrocarbon stream. into apropylene disproportionation Zone;

We claim: separating the eiiiuent of said disproportionation zone 1. Aprocess for producing ethylene, butadiene, a high and returning a streamtherefrom comprising C3 aromatic content `carbon black feedstock, andbenzene, hydrocarbons to said separation zone and passing comprising thesteps of: a stream therefrom comprising C4 hydrocarbons to cracking anaphtha stream in a naphtha cracking zone;

removing fuel oil from the efliuent of said naphtha cracking zone andpassing the remaining portion into a separation zone;

removing a C4 hydrocarbon stream from -said separation Zone and passingsaid C4 hydrocarbon stream into a butadiene recovery zone;

removing a butadiene stream from said butadiene recovery zone;

said butene deoiling zone; and removing ethylene from said separationzone. 2. A process for producing butadiene, a heavy aromatic contentcarbon black feed stock, and benzene, comprising the steps of:

cracking a naphtha stream in a naphtha cracking zone; removing fuel oilfrom the efuent of said naphtha cracking zone and passing the remainingportion into a first debutanizing zone;

removing a butene-isobutylene stream from said butain Said rStdehlltahizirlg Z0he Separating e light Stream diene recovery zone andpassing said butene-iso- Comprising butene and lighter COIhPOheIltS anda butylene stream into an isobutylene removal zone; gaSOlHe StreamCOmPrShg heavier COmPOrlehtS;

removing a butene-containing stream from said isofeeding a light streamfrom said debutanizing zone to butylene removal zone and passing saidbute-nea depropanizing zone; containing stream into a butene deoilingzone; in said depropanizing zone separating a light stream removing abutene stream from said butene deoiling comprising propane and lighterand a heavy stream zone and passing said butene stream to a butenedecomprising butanes, butenes and butadienes; hydrogenation zone;feeding said heavy stream from said depropanizer passing the ethuentfrom said butene dehydrogenation to a butadiene removal zone;

zone to said separation zone; in said butadiene removal zone, separatingthe butaremoving a gasoline stream from said separation Zone; dieneproduct stream comprising substantially all of removing from saidisobutylene removal unit a stream said butadiene and a minor amount ofsaid butenes comprising isobutylene removed in said unit; and adehydrogenation feed stream comprising subremoving an oil stream fromsaid buteneV deoiling stantially all of said butanes and a predominantzone; amount of said butenes;

passing said gasoline stream, said stream comprising dividing saiddehydrogenation feed stream into a major isobutylene and said oil-stream into a hydrotreating portion and a minor portion; zone; feedingsaid minor portion of said dehydrogenation passing hydrogen into saidhydrotreating zone and feed stream to a second debutanizing zone;

hydrotreating said gasoline stream, said stream comin said seconddebutanizing zone removing a butene prising isobutylene and said oilstream therein; stream and a debutanized stream;

passing the effluent from said hydrotreating zone into combining saiddebutanized stream with said major an aromatic extraction zone; portion;

passing aromatics from said aromatic extraction zone passing thecombined stream of said major portion into a benzene separation Zone;and said debutanized stream to an isobutylene reremoving benzene fromsaid benzene separation zone; moval zone;

removing a heavy aromatic stream from said benzene in said isobutyleneremoval Zone, separating a stream separation zone; comprisingisobutylene from said combined stream;

blending said fuel oil and said heavy aromatic stream passing theremainder of said combined stream into a to produce a carbon black feedstock; butene deoiling zone;

in said deoiling zone removing an oil fraction and passing the remainderto a dehydrogenation zone;

combining the effluent of said dehydrogenation zone with said effiuentfrom said cracking zone;

passing said gasoline stream, said stream comprising isobutylene andsaid oil stream into a hyrotreating zone;

passing hydrogen int-o said hydrotreating zone and hydrotreating saidgasoline stream, said stream comprising isobutylene and said oil streamtherein;

passing the efliuent from said hydrotreating zone into an aromaticextraction zone;

passing aromatics from said aromatic extraction zone into a benzeneseparation zone;

removing benzene from said benzene separation zone;

removing a heavy aromatic stream from said benzene separation zone;

blending said fuel oil and said heavy aromatic stream to produce acarbon black feed stock; and

recycling paraflins and oleiins from said aromatic extraction zone tosaid naphtha cracking zone.

3. A process for producing ethylene, butadiene, a high aromatic contentcarbon black feed stock, and benzene, comprising the steps of:

cracking a naphtha stream in a naphtha cracking zone;

removing fuel oil from the eiiiuent of said naphtha cracking zoneV andpassing the remaining portion into a first debutanizing zone;

in said first debutanizing zone separating a light stream comprisingbutene and lighter components and a gasoline stream comprising heaviercomponents; feeding a light stream from said debutanizing zone to adepropanizing zone;

in said depropanizing zone separating a light stream comprising propaneand lighter and a heavy stream comprising butanes, butenes andbutadienes;

feeding said heavy stream from said depropanizer to a butadiene removalzone;

in said butadiene removal zone, separating the butadiene product streamcomprising substantially all of said butadiene and a minor amount ofsaid butenes and a dehydrogenation feed stream cornprising substantiallyall of said butanes and a predominant amount of said butenes;

dividing said dehydrogenation feed stream into a major portion and aminor portion;

feeding said minor portion of said dehydrogenation feed stream to asecond dibutanizing zone;

in said second debutanizing zone removing a butene o stream and adebutanized stream;

combining said debutanized stream with said major portion;

passing the combined stream of said major portion and said debutanizedstream to an isobutylene removal zone;

in said isobutylene removal zone, separating a stream comprisingisobutylene from said combined stream;

passing the remainder of said combined stream into a butene deoilingzone;

in said deoiling zone removing an oil fraction and passing the remainderto a dehydrogenation zone;

combining the eliiuent of said dehydrogenation zone with said effluentfrom said cracking zone;

passing said gasoline stream, said stream comprising isobutylene andsaid oil stream into a hydrotreating zone;

passing hydrogen into said hydrotreating zone and hydrotreating saidgasoline stream, said stream cornprising isobutylene and said oil streamtherein;

passing the efliuent from said hydrotreating zone into an aromaticextraction zone;

passing aromatics from said aromatic extraction zone into a benzeneseparation zone;

removing benzene from said benzene separation zone;

removing a heavy aromatic stream from said benzene separation zone;

blending said fuel oil and said heavy aromatic stream to produce acarbon black feed stock;

recycling parafiins and olelins from said aromatic extraction zone tosaid naphtha cracking zone;

removing a C4 hydrocarbon stream from said separation zone and passingsaid C3 hydrocarbon stream into a propylene disproportionation zone;

separating the efiluent of said disproportionation zone and returningthe stream therefrom comprising C2 hydrocarbons to said separation zoneand passing a stream therefrom comprising C4 hydrocarbons to said butenedeoiling zone; and

removing ethylene from said separation zone.

4. A process for producing butadiene, ethylene, a high aromatic contentcarbon black feed stock, and benzene, comprising the steps of:

cracking a naphtha stream;

passing the eiuent of said naphtha cracking zone into a heat recoveryand quench zone;

removing a fuel oil stream from said heat recovery and quench zone;

passing the remainder of the effluent of said naphtha cracking zone intoa irst flash zone;

passing condensate from said first fiash zone into a second flash zone;

passing vapor from said rst flash zone through a caustic wash and drytreatment into a third flash zone;

passing vapor from said third flash Zone into a fourth flash zone;

passing condensate from said fourth flash zone into a first fractionaldistillation column;

passing bottoms product from said first fractional distillation columninto a second fractionation column;

recovering ethylene overhead from said second fractional distillationcolumn;

passing condensate from said third liash zone and vapor from said secondflash zone into a third fractional distillation column;

returning overhead product from said third fractional distillationcolumn to said second fractional distillation column;

removing a side stream from said third fractional distillation columnand passing said side stream to a propylene disproportionation unit;

returning the product from said propylene disproportionation zone tosaid third fractional distillation column;

flashing bottoms product from said third fractional distillation columninto a furfural absorber;

recovering butadiene from said furfural absorber;

removing rafiinate from said furfural absorber;

removing butanes from a side stream of said raffinate and returning theremainder of said side stream to an isobutylene removal unit;

removing isobutylene from said isobutylene removal unit;

passing the isobutylene free stream from said isobutylene removal unitinto a fourth fractional distillation column;

passing an overhead stream from said fourth fractional distillationcolumn, comprising butenes, into a butene dehydrogenation zone;

returning etiiuent from said butene dehydrogenation zone to said firstflash zone;

passing a gasoline stream removed as condensate from said second flashzone, a stream comprising isobutylene from said isobutylene removalunit, and an oil stream removed as a bottoms product from said fourthfractional distillation column into a hydrotreating zone;

blending said fuel oil and said heavy aromatic stream to produce acarbon black feed stock; and

recycling paraffin and olens from said aromatic eX- traction zone tosaid naphtha cracking zone.

No references cited.

DELBERT E. GANTZ, Primary Examiner.

H. LEVINE, Assistant Examiner.

1. A PROCESS FOR PRODUCING ETHYLENE, BUTADIENE, A HIGH AROMATIC CONTENT CARBON BLACK FEEDSTOCK, AND BENZENE, COMPRISING THE STEPS OF: CRACKING A NAPHTHA STREAM IN A NAPHTHA CRACKING ZONES; REMOVING FUEL OIL FROM THE EFFUENT OF SAID NAPHTHA CRACKING ZONES AND PASSING THE REMAINING PORTION INTO A SEPARATION ZONE; REMOVING A C4 HYDROCARBON STREAM FROM SAID SEPARATION ZONE AND PASSING SAID C4 HYDROCARBON STREAM INTO A BUTADIENE RECOVERY ZONE; REMOVING A BUTADIENE STREAM FROM SAID BUTADIENE RECOVERY ZONE; REMOVING A BUTENE-ISOBUTYLENE STREAM FROM SAID BUTADIENE RECOVERY ZONE AND PASSING SAID BUTENE-ISOBUTYLENE STREAM INTO AN ISOBUTYLENE REMOVAL ZONE; REMOVING A BUTENE-CONTAINING STREAM FROM SAID ISOBUTYLENE REMOVAL ZONE AND PASSING SAID BUTENECONTAINING STREAM INTO A BUTENE DEOILING ZONE; REMOVING A BUTENE STREAM FROM SAID BUTENE DEOILING ZONE AND PASSING SAID BUTENE STREAM TO A BUTENE DEHYDROGENATION ZONE; PASSING THE EFFUENT FROM SAID BUTENE DEHYDROGENATION ZONE TO SAID SEPARATION ZONE; REMOVING A GASOLINE STREAM FROM SAID SEPARATION ZONE; REMOVING FROM SAID ISOBUTYLENE REMOVAL UNIT A STREAM COMPRISING ISOBUTYLENE REMOVED IN SAID UNIT; REMOVING AN OIL STREAM FROM SAID BUTENE DEOILING ZONE; PASSING SAID GASOLINE STREAM, SAID STREAM COMPRISING ISOBUTULENE AND SAID OIL STREAM INTO A HYDROTREATING ZONE; PASSING HYDROGEN INTO SAID HYDROTREATING ZONE AND HYDROTREATING SAID GASOLINE STREAM, SAID STREAM COMPRISING ISOBUTYLENE AND SAID OIL STREAM THEREIN; PASSING THE EFFLUENT FROM SAID HYDROTREATING ZONE INTO AN AROMATIC EXTRACTION ZONE; PASSING AROMATICS FROM SAID AROMATICS EXTRACTION ZONE INTO A BENZENE SEPARATION ZONE; REMOVING BENZENE FROM SAID BENZENE SEPARATION ZONE; REMOVING A HEAVY AROMATIC STREAM FROM SAID BENZENE SEPARATION ZONE; BLENDING SAID FUEL OIL AND SAID HEAVY AROMATIC STREAM TO PRODUCE A CARBON BLACK FEED STOCK; RECYCLING PARAFFINS AND OLEFINS FROM SAID AROMATIC EXTRACTION ZONE TO SAID NAPHTHA CRACKING ZONE; REMOVING A C3 HYDROCARNON STREAM FROM SAID SEPARATION ZONE AND PASSING SAID C3 HYDROCARBON STREAM INTO A PROPYLENE DISPROPORTIONATION ZONE; SEPARATING THE EFFLUENT OF SAID DISPROPORTIONATION ZONE AND RETURNING A STREAM THEREFROM COMPRISING C3 HYDROCARBONS TO SAID SEPARATION ZONE AND PASSING STREAMS THEREFROM COMPRISING C4 HYDROCARBONS TO SAID BUTENE DEOILING ZONE; AND REMOVING ETHYLENE FROM SAID SEPARATION ZONE. 